#include <bits/stdc++.h>

int main() {

  int x, y, x2, y2;

  std::cin >> x >> y >> x2 >> y2;

  if( x == y && x2 == y2 && x2 < x ) {
    std::cout << std::max(x, y) + 1 << std::endl;
  }
  else {
    std::cout << std::max(x, y) << std::endl;
  }
  
  return 0;
}